ScY@C3v(8)‐C82: Metal‐Metal σ2 Bond in Mixed Rare‐Earth Di‐metallofullerenes†.

Comprehensive Summary: The experimental investigation of rare‐earth metal‐metal bonds remains a challenge in the study of chemical bonds. Herein, we report the synthesis and characterization of a novel heteronuclear di‐metallofullerene, ScY@C3v(8)‐C82, which contains a mixed rare‐earth metal‐metal bond. ScY@C3v(8)‐C82 was successfully synthesized by arc‐discharging method and characterized by mass spectrometry, UV‐vis‐NIR spectroscopy and single‐crystal X‐ray diffraction crystallography, which unambiguously determined its molecular structure. Theoretical calculations were also performed to study the optimized positions of Sc‐Y metallic dimer and the electronic configuration. The combined experimental and theoretical results confirmed that both Sc and Y atoms transfer two electrons to the C3v(8)‐C82 cage, i.e., (ScY)4+@(C3v(8)‐C82)4–. In particular, a covalent Sc‐Y σ2 bond, which has never been reported before, is proven to be formed inside C3v(8)‐C82 fullerene cage. This work presents a novel di‐metallofullerene containing mixed rare‐earth metal‐metal bond and expands the understanding of metal‐metal bonding of rare earth elements. [ABSTRACT FROM AUTHOR]